Lapping machine



Dec. 14 1926.

H. I.. VAN KEUREN l LAP'PING MACHINE Filed Nev. 26, 1921 Patented Dec. 14, 1926.

lurural- STATES morn L. VAN KEUREN, on Bos'roN,

MASSACHUSETTS, AssIeNoR :no BETHEL- PLAYEB. co., A @PARTNERSHIPooNsIsrING on JOSEPH N. BETHEL AND sIDNEY PLAYEB, or wns'rnono,MASSACHUSETTS.1

'LAPPINQ MAcHrNE I Application iil'edyNovemberi chine which lis particularly adaptedto the productionof cylindrical' workv and to .cer tain .methods 'the practicev :of `wfhich Ais exemplified'by the operation vof the machine disclosed@` The purpose' of .the invention'is to provide means 4for the" rapid and .accurate production ,of such articles as bearing rollers',y

' units, or" any -machine element requiring straight and uniform cylindrical'surfaces..

My invention will best b e understood-by" reference'to the following. descriptionof the illustrative embodiment thereof -shown by fying my invention; and f f "FigL'2 is a plan view thereof `with the j .ln .accordance with my vide a machine capable. of finishing a considerable number of rolls atal single opera' tion as contradistinguished .romjhe grinding of rolls one'at a time.` `Referringto the drawings,f I preferably utilize, 'fiat ringshapedlapsa and b. @Such dat; laps, of any suitable material or prepared with a lapping surface in any desiredI way, maybe easily maintained flat by rubbing three of them toj gether with anabradant in accordance with' the commonly known practice for securing Hat surfaces. The two laps a and b oppose each otherand are differentially rotated with the work between them and conveniently' the lap a is stationary, being held .on a suitable support, and the lap b is pressed toward the same'. by itsl own-weight reinforced, iff de.- sired, by vweights or springs. The lap'l is .rotated and l have herein -shown' the square end of a shaft d' taking into-a spider esecured to the lap b and adapted to be rotated by the belt lhe surfaces of thelaps being perfectlyl at.,l they do not require accurate alignment nor must the work holder be accurately positioned. as inthe case of grind-4 ing machines.- During operation the two laps are spaced by the work such as the rollers gend these are held in position 'between the working face of the laps 'by be- 1 invention prof bined rollin 26, "1921. serieu No. 517,912.5

in a disc or cage 'e' 'which Iis interposed between the laps. vAdjustable' postslc in the table o may be vprovided for centering the work receiving'disc or cage e' between the laps so that' it willembra'ce therollers g substantially centrally of their diameters.

` produced lin the rough-for eXamp e, they may be #sections of a .round rod-artdare placed in the 'slots it on their sides. As distin snob. asgage blocks as'ihitherto practiced, the rollers g must be permitted to rollin order `that -they 'may be. uniformly lapped down. At `the same time-there .must be a relative .sliding motion betwen the lapping surfaceand the work in order to permitthe lformer to `.cut or'4 grind the latterV but if such move'- 'mentis localized by .failure of the work to Tlierollers 'g'lwhich are to belap ed are l ished from the lapping -of flat` blocks` rotate, Hat surfaces will be produced dev f stroying thel accuracy of the work. A comp and sliding motion is secured inthe machlne shownby placing the slots Ji, which are. arranged around a circle the diameterv of which preferably corresponds to the mean diameter of. the laps a' vand b, a position oblique to radii ofthe disc. The action `will best be understood by considering the limiting cases.. lfthe slots'were radial, clearly the rollers would simply be rotated on their own axes between .the two 1a s and no sliding or lapping motion woul take place. If the rolls were placed lengthwise around theA circumference of a circle-of the same mean diameter as the. lapping faces, the' motion would be all slidin with no rolling component and consequen y 1two flat surfaces would be produced .on thepieces being lapped instead'of the desired cylindrical surfaces. The angle .of .the slots h may be varied, with the rate of lapping desired .but .an'lanigle of 45 as illustrated may be used.

Toinsureuniform'wear. ofthe laps a and b and te prevent any portigmthereofl from being unduly worn or stripped of abradant,

provision is made to distribute the wear over their entire width. -v inthe ordinary instance the rolly or rolls in each of theslots h will not y.be as wide as the face of the laps a and b and to cause them to move across vthe face of these laps the disc i may be rotated about. a center' eccentric to the center of the laps so as. to move the-Work back and forth across diameter of the'laps.

Athese faces.v In the present instance the crank m is provided on 'a central Ashaft havting a crank pin' loosely received inacentral opening in the disci.H The.` throwl of thai crank may' be equal izo-.approximately half thefwidthof the' .face.of the laps'aand b,

this providin for.v moving completelyacross' the faces oft e. lapsy the. workin the--slots-t.Y`

which, 'as' stated', are vpreferably ranged around a circle of diameter equal to the mean The work holder zmay be permitted to be revolve-'freely between thelaps a and b by the reaction of thejlatterI and .in this case it will gyrate since it will. rotate about its own center. and this center will also be forced tao-move through a small circularpath by means of the crank m. rlhe path of the rollers .g vwhich. are. being actedupon. willn thus -be an epicyclic and'while being moved in this path they will be heldby the slots h in a position obl-ique to a radius of one of rolling action over the'entire faces yofthe ile thediscd may be left entirely freeY I preferably arrange for driving the Yshar't of the crankm at a relatively'slow rate, this being indicated in the drawing by the repre work disc, rearrang t lapping operationiqto equalize. the Werk..A The idea of .promiscuously .mixing up worlg'f and returning it fora continuance of an" sentation of the gear train n. For example,

the upper lap' b may be rotated at the rate of revolutions per minute and the shaft ofthe crank'm at about 10 rev'olutions per minute. The directiom of rotation of: the

center of the work disc maybe in the same or the op site direction as that of the lrotating lap but'I`. 'pre-fer' to .rotate it. in one direction :for one'o'r more` revolutions and then the opposite directioncontinually. repeatiathe cycle. -By this'means the wear.

on both-.t e .stationary lap-a-,and theJ rotating lap bare made .exactly equal.` w AfterI the -lappinV operation has proceeded for a certain lengt of vtime may be'that I thework has proceeded futher"at one'p'oint? along the .workdiscf'than at `another -and it is desirable.' tovrenive. all the'paits from 'the hem. and. continue the operation is not-novel but. I provide .for af e rolls g ina novel manner. Referringv to I lig. 2,1 pref` lap, a rotated lap, a work holder mounted systematic rearrangement of tv erably make the number of, slots'h in the,

Work disc.. a suitable multiple. ofsiz. For

example, I .have hereshown twenty-four.

After the work has proceededalternatei rollers are shifted around the vcircumference Y of the work discf120 or oftheci'r'cumference. Thus, referring=to thedr'avving,

the odd numbered rolls are left in the positionto approximately' 1200 apart.

rated,

` reicher tion indicated. The ,roll formerly in slot 2 is shifted to 10, 10. to 18 and 18 to 2. The next transposition .is preferably in the reverse direction.l The previous transposition being clo'ckwise, 4 is shifted counterclockwise to Q0, 2() to 1 2 and 12 to 4. The innen numerals'represent the original positions of the'l parts and theouter numerals the new originally adjacent are shifted to a new posi- 'lhus orginal rolls 6, 7 and 8 were relatively h1gh efore, they arethen distributed around the circle and any inaccuracy of the preceding operation Ais distributed. Futhermore,

it will be recalled that three points 'deter-v mine a` plane and therefore if there was a .local Yhigh point in the-precedingoperationj this maximum after the transposition occurs at three points around l.the circle and` the upper lap isin substantial parallelism with the lower lap ready for. unitary action. In contrast, if the shifting had been diametrical, the rolls of maximum heightmght be v .found *opposite each other and the laps might tilt or teeter on the high point.

Vpositions#.By-this. means rollsjwhichv-werei 1t will, of course, be understood that while"V Y l l y .I have herein illustrated one circular series of slots h, there might be a plurality of such l series.

05 Thel lapping operation may be carried out in two or more steps utilizing laps of differl l ent degrees offineness.

Having thus described in detail the particular embodiment of my invention shown' by way of examplein the accompanying drawings, the principles exemplified therebyj which I claim as new and desire to secure 'by Letters Patent I shall express in the following claims.

' 1. A lapping 'machine comprising opposed iiatfacelaps, oneof which is positively r0-V a freely rotatable work f holder mounted between the laps and having openingsto receive and position pieces of work, and driving means for ysaid work holder 'effective' to move. the axis of the work holder in a circular path, such movement beiner supplemental` to v the free rotation'. of Vsaid disc -and :being at a slower speed of rotation than the movement of the positively rotated lap and -also being" in a circular path of'.

smalll diameter -and dsaid diameter -being 'much les'shan the diameter of the work 2'. A'lapping machine "comprisinga fixed i between said laps, positive means to move said'work holder-*between said laps'at a predetermined speed relative tothe movementv Awork holder' with. the axis of the vcylindrical vlao pieces oblique to radial linesiin said liolde'r and passing through said pieces, whereby a combined rolling and sliding movement of said Acylindrical pieces over the surfaces of the laps is attained.

3. The combination in a lapping machine as setv forth in claim 2, in which the means to drive the Work holderrotates at a differentspeed from the. rotated lap, causing l between said laps and means .to positively.

- move said Work holder in a plane parallel to and between saidlaps at a different speed from said rotated lap and in a path eccentric to the axis of said rotated lap, said Work holder being also freely vrotatable about its own axis.

5. A lapping machine having, in combination, a 4fixed lap, a positively rotated lap, an eccentric bearing member mounted to ro* tate at a speed different from'that of said,

rotated lap, and a Work holder freely rotatable about said eccentric bearing member.

6. A lapping machine having, in combination :1 fixed lap, a positively rotated lap, an eccentric bearing member mounted on a support to rotate about the axis of .said rotatable lap, means to rotate said lap and vbearing member Support at relatively different speeds,landa Work holder freely roy35 tatable about saidvb'earing member.

In testimony whereof I have signed my A name to this specification.

HAROLD L. VAN KEUREN.l 

